Many processes are known in the art for the carbonylation of acetylenically and olefinically unsaturated compounds. A review of such processes is provided by J. Falbe, "New Syntheses with Carbon Monoxide", Springer-Verlag, Berlin Heidelberg New York, 1980. Typically, the processes involve the reaction of an acetylenically or olefinically unsaturated compound with carbon monoxide and, in some cases, a nucleophilic compound having a removable hydrogen atom, in the presence of a carbonylation catalyst system. In many instances, the carbonylation catalyst system comprises a source of a Group VIII metal and a ligand such as a phosphine.
Recently, several processes for the carbonylation of acetylenically and olefinically unsaturated compounds have been disclosed which involve the use of a carbonylation catalyst system comprising a Group VIII metal compound, in particular a palladium compound, a phosphine and a protonic acid. The processes proceed with a remarkably high reaction rate.
European Patent Nos. EP-A1-106379. EP-A1-235864. EP-A1-274795 and EP-A1-279477 disclose processes for the carbonylation of olefinically unsaturated compounds in which a catalyst system comprising a palladium compound, a triarylphosphine and a protonic acid is used. In all of the examples, the triarylphosphine used is a triphenylphosphine.
European Patent No. EP-A1-0186228 discloses a process for the carbonylation of acetylenically unsaturated compounds in which a catalyst system comprising a palladium compound, a phosphine and a protonic acid is used. The examples illustrate the use of optionally substituted hydrocarbyl phosphines such as triphenylphosphine.
More recently, several processes for the carbonylation of acetylenically and olefinically unsaturated compounds have been disclosed which involve the use of a catalyst system comprising a palladium compound, a pyridylphosphine and an acid.
European Patent Nos. EP-A1-259914, EP-A1-282142 and EP-A1-305012 disclose processes for the carbonylation of olefinically unsaturated compounds in which a catalyst system comprising a palladium compound, a pyridylphosphine and a protonic acid is used.
European Patent No. EP-A1-0271144 discloses a process for the carbonylation of an acetylenically unsaturated compound in which a catalyst system comprising a palladium compound a pyridylphosphine and a protonic acid is used.
None of the aforementioned European patent specifications disclose catalyst systems which additionally comprise a tertiary amine, nor do they suggest that such catalyst systems would be of interest in the carbonylation of acetylenically and olefinically unsaturated compounds. Tertiary amines are basic compounds and so might be expected to have a marked inhibitory effect upon the performance of the acid-containing catalyst system. Indeed, the Applicants have found that the performance of triarylphosphine-based catalyst systems is markedly impaired in the carbonylation of olefins when a tertiary amine is included.
It, however, has now been found that acetylenically and olefinically unsaturated compounds can be carbonylated at a good reaction rate using a catalyst system comprising a palladium compound, a pyridylphosphine, a protonic acid and a tertiary amine.